Production of coloring matters



Patented Mar. 24, 1925.

UNITED STATES PATENT OFFICE-.1

ARTHUR HUGH DAVIES, DECEASED, LATE 0F WILLENHALL, ENGLAND; BY MARY OLIVIA DAVIES, ADMINISTRATRIX, OF WILLENHALL, ENGLAND; AND ROBERT FRASER THOMSON, OF CARLISLE, ENGLAND, ASSIGNORS TO SCOTTISH VDYES,

LIMITED, OF CARLISLE, CUMBERLAND COUNTY, ENGLAND.

PRODUGTTON OF COLORING MATTERS.

No Drawing. Original application filed November. 14, 1921, Serial No. 515,087. Divided and this application filed August 24. .1923. Serial No. 659,238.

To all-70. 10121, it may concern:

Be it known that we, MARY OLIVIA DAVIES, administratrix of the estate of the late ARTHUR HUGH DAVIES, a subject of the King of Great Britain and Ireland, and residing at 72 New Road, Willenhall, in the county of Stafi'ord, England, and ROBERT FRASER THOMSON, a subject of the King of Great Britain and. Ireland, and residing at Murrell Hill Works, Carlisle, in the county of Cumberland, England, do hereby declare that the said ARTHUR HUGH DAVIES, de-' ceased, and ROBERT FRASER THOMSON have invented certain new and useful Improve ments in the Production of Coloring Matters, of which the following is a specification.

This invention relates to the production of a. coloring matter or dyestufi' of the anthracene series. I

. It has for its object to provide an improved or new coloring matter from the known oxidation product of dibenzanthrone.

' The invention consists in the production of a coloring 111atter'by"the methylation of the oxidation product "of dibenzanthrone, preferably by dimethyl sulphate.

The following examples are given to illustiifate methods of carrying the invention into e ect-:

E wmnple A.

Ten parts of the dried oxidation product of dibcnzanthrone are suspended in one hun-i dred parts of dry nitrobenzene and ten parts of dry shdium carbonate added along with ten parts of dime-thyl sulphate. A rise in temperature occurs and the mixture is then heated to boiling for three hours, cooled and 10 parts of sodium carbonate dissolved in 200 parts of water added, and the nitrobenzene distilled 01f by means of steam. The product is filtered off and may be used dimet as a dyestufl' paste. It consists of a blue-green aste, which dissolves in alkaline hydrosulphite with a blue colour and dyes. cotton bright greenish-blue shades, which shades are fast to the action of chlorine and acids. The dry product dissolves in sulphuric acid with a red-violet colour which is unaltered by addition of a reducing agent such as metallic copper.

E mample B v The methylated dyestufi' described in Example A may be separated in a pure form by the following method The nitrobenzene solution obtained at the end of the alkylation is filtered while still hot, yielding a greenish-blue filtrate. The undissolved residue is extracted with boiling nitrobenzene until no more dyestufi' dissolves, the solution being then filtered and the combined filtrates evaporated to a small bulk and allowed to cool. The dyestuff crystallizes out and is filtered off and washed with alcohol. The product consists of a brilliant greenish-blue powder dissolving in strong sulphuric acid with a brilliant redviolet colour, which on slow dilution with Water becomes first bros-mowing to the formation of the sulphuric acid compound, and finally brilliant bluish-green. The dyestufl may be used in the form of a powder or may be converted into paste by dissolving in strong sulphuric acid and rep-recipitating with water, or by dissolving in alkaline hydrosulphite and blowing the dyestufi' out again with air.

The product appears to be dimethoxydibenzanthrone which may be regarded as formed by the combination of one molecule of dibenzanthrone, two molecules of methyl sulphate and one molecule of sodium car bonate according to the following equat1on:

An approximate analysis of the dyestufi' gives the following results P r n a 0.011, 1ft, o; 83.5 H 4.8

- By calculation the theoietical equivalents in 'dimethoxydibenzanthrone are as ,follows:- 7

Per cent.

These figures therefore show a close resemblance particularly having regard to the fact that onlyithe results of an approximate analysis are given.

a Ewample0.

The crude methylated dyestufl obtained in Example A may be purified by suspend ing 1 part in 10 parts of water, adding 1; part of sodium chlorate, bringing to the boil,- and adding slowly 3 parts of commercial hydrochloric acid. The *mixture is then boiled for 1 hour,diluted. and filtered. The impurities in the original product are now present in the form of alkali soluble bodies and may be removed by dissolving in weak alkali and filtering. The purified bodyconsists of a green paste which may be used directly as a dyestufi' and is in all respects identical with the product described in Example B.

Example D.

The methylated dyestufl describedin Example fA forms a compound by combination with sulphuric acid, which compound may be used for purifying and isolating the colour. W V

1 part of methylated product is dissolved with stirring in 25 parts of 96% sulphuric acid. To this, water is cautiously added to reduce the concentration of sulphuric acid to 80%. The sulphuric acid compound separates out as a brown amorphous precipi-v tate. This is filtered off over asbestos and washed with 80% acid, until the filtrates are no longer coloured brown. The precipitate of the sulphuric acid compound, which is of a brown colour, is boiledup with water, which converts it into a brilliant bluishgreen paste, and this is then filtered off, washed with water, when it can be used directly for dyeing. The sulphuric acid filtrates contain impurities of little value.

In the above examples we have used nitro .benzol as the medium for carrying out the treatment with dimethyl sulphate but we do not confine ourselves to the use of nitrobenzol, as the reaction can be carried out quite readily in other solvents which do not interfere with the reaction, such as nitrotoluol, naphthalene. The reaction may also be carriedout without a diluent in the presence 1 of dimethyl sulphate.

Having now described our invention,

matter which comprises the methylation of the oxidation product of dibenzanthrone.

2. The 'process of producing a coloring matter which comprises the methylation of the oxidation product of dibenzanthrone with dimethyl sulphate.

3. As a new article of manufacture the coloring matter obtainable by treating the oxidation product of dibenzanthrone with dimethyl sulphate which consists of a bluegreen paste which dissolves in alkaline hydrosulphite with a blue colour and dyes cotton bright greenish-blue shades which are fast to the action of chlorine and 'acids. 4t. As 'a new article of manufacture the coloring matter obtainable by treating the oxidation product of dibenzanthrone with dimethyl sulphate which consists when dry of a product that dissolves in sulphuricacid with a red-violet colour which is unaltered by addition of metallic copper.

5. Aprocess for the production of a dyestuff which comprises the treatment of an oxidationproduct of dibenzanthrone with ;dimethyl sulphate followed by crystallization from a nitrobenzene solution.

6. As a new article of manufacture a purified dyestulf prepared according to the process claimed in claim 5, which consists of a brilliant greenish-blue powder dissolving in strong sulphuric acid with a brilliant red-violet colour which on slow dilution with water becomes first brown and finally brilliant bluish-green.

7. A process for the production of a coloring matter which comprises the treatment of the oxidation product of dibenzanthrone with dimethyl sulphate and subsequent combination withsulphuric acid.

8. The product of the process claimed in iclaim 7, which consists in a brown amorphous precipitate which when boiled with water is converted into a brilliant bluishgreen substance which can be used directly for dyeing.

9. Dimethoxydibenzanthrone.

10. Materials dyed by dimethoxydibenzanthrone.

In testimony whereofwe have signed our names. to this s ecification.

MARY LIVIA DAVIES, Administratflw of Arthur Hug/2, Davies,

deceased. l 7

ROBERT FRASER THOMSON. 

